Functions of Gibberellic Acid(GA3)

Gibberellic acid (GA3) can promote seed germination, plant growth, and early flowering and fruiting. It is widely used in a variety of food crops, and is even more widely used in vegetables.It has a significant promotion effect on the production and quality of crops and vegetables.

1.Physiological functions of gibberellic acid (GA3)
gibberellic acid (GA3) is a highly effective general plant growth promoting substance.

It can promote plant cell elongation, stem elongation, leaf expansion, accelerate growth and development, make crops mature earlier, and increase yield or improve quality;      it can break dormancy and promote germination;
reduce shedding, improve fruit setting rate or form fruitless fruits.      Seeds and fruits;   can also change the sex and ratio of some plants, and cause some biennial plants to bloom in the same year.

(1) gibberellic acid (GA3) and cell division and stem and leaf elongation

gibberellic acid (GA3) can stimulate the internode elongation of stems, and the effect is more significant than auxin, but the number of internodes does not change.
The increase in internode length is due to cell elongation and cell division.

Gibberellic acid (GA3) can also elongate the stems of dwarf mutants or physiological dwarf plants, allowing them to reach the height of normal growth.
For dwarf mutants such as corn, wheat, and peas, treatment with 1mg/kg gibberellic acid (GA3) can significantly increase the length of internode and reach normal height.

This also shows that the main reason why these dwarf mutants become shorter is Missing gibberellic acid (GA3).
Gibberellic acid (GA3) is also used to promote the elongation of grape fruit stalks, loosen them, and prevent fungal infection. It is generally sprayed twice, once during flowering and once during fruit setting.

(2) gibberellic acid (GA3) and seed germination
gibberellic acid (GA3) can effectively break the dormancy of seeds, roots, tubers and buds and promote germination. 

For example, 0.5~1mg/kg gibberellic acid (GA3) can break potato dormancy.

(3) gibberellic acid (GA3) and flowering
The effect of gibberellic acid (GA3) on plant flowering is relatively complex, and its actual effect varies depending on the type of plant, application method, type and concentration of gibberellic acid (GA3). 

Some plants need to experience a period of low temperature and long daylight before flowering. Treatment with gibberellic acid (GA3) can replace low temperature or long daylight to make them bloom, such as radish, cabbage, beet, lettuce and other biennial plants.

(4) gibberellic acid (GA3) and sexual differentiation
The effects of gibberellins on sexual differentiation of monoecious plants vary from species to species. gibberellic acid (GA3) has a female-promoting effect on gramineous corn.

Treatment with gibberellic acid (GA3) at different stages of development of young corn inflorescences can make the tassels feminized or the male flowers sterile respectively. In melons, gibberellic acid (GA3) can promote the differentiation of male flowers, while in bitter melon and some varieties of luffa, gibberellin can promote the differentiation of female flowers.

Treatment with gibberellic acid (GA3) can induce parthenocarpy and produce seedless fruits in grapes, strawberries, apricots, pears, tomatoes, etc.

(5) gibberellic acid (GA3) and fruit development
Gibberellic acid (GA3) is one of the necessary hormones for fruit growth. It can promote the synthesis and secretion of hydrolase and hydrolyze storage substances such as starch and protein for fruit growth. gibberellic acid (GA3) can also delay fruit ripening and regulate the supply, storage and transportation time of fruits and vegetables. In addition, gibberellic acid (GA3) can stimulate parthenocarpy in a variety of plants and can also promote fruit setting.

2.Application of gibberellic acid(GA3) in production
(1) gibberellic acid (GA3) promotes growth, early maturity, and increases yield

Many green leafy vegetables can accelerate growth and increase yield after being treated with gibberellic acid (GA3).  Celery is sprayed with 30~50mg/kg gibberellic acid (GA3) solution about half a month after harvesting.

The yield will increase by more than 25%, and the stems and leaves will become enlarged.  It will be available for market for 5~6 days in the morning.  Spinach, shepherd's purse, chrysanthemum, leeks, lettuce, etc. can be sprayed with 1.  5~20mg/kg gibberellic acid (GA3) liquid, and the yield increase effect is also very significant.

For edible fungi such as mushrooms, when the primordium is formed, soaking the material block with 400mg/kg liquid can promote the enlargement of the fruiting body.
For vegetable soybeans and dwarf beans, spraying with 20~500mg/kg liquid can promote early maturity and increase yield.  For leeks, when the plant is 10cm high or 3 days after harvesting, spray with 20mg/kg liquid to increase yield by more than 15%.


(2) gibberellic acid (GA3) breaks dormancy and promotes germination
The vegetative organs of potatoes and some vegetable seeds have a dormant period, which affects reproduction.

Cut potato pieces should be treated with 5~10mg/kg liquid for 15min, or whole potato pieces should be treated with 5~15mg/kg liquid for 15min.  For seeds such as snow peas, cowpeas, and green beans, soaking them in 2.5 mg/kg liquid for 24 hours can promote germination, and the effect is obvious. 

 Using 200 mg/kg gibberellic acid (GA3) to soak the seeds at a high temperature of 30 to 40 degrees for 24 hours before germination can successfully break the dormancy of lettuce seeds.

In strawberry greenhouse promoted cultivation and semi-promoted cultivation, after the greenhouse is kept warm for 3 days, that is, when more than 30% of the flower buds appear, spray 5 ml of 5~10 mg/kg gibberellic acid (GA3) solution on each plant, focusing on the core leaves, to make the top inflorescences Flowers earlier, promotes growth, and matures earlier.

(3) gibberellic acid (GA3) promotes fruit growth
For melon vegetables, spraying the young fruits with 2~3 mg/kg liquid once during the young melon stage can promote the growth of young melons, but do not spray the leaves to avoid increasing the number of male flowers.

For tomatoes, spray flowers with 25~35mg/kg during the flowering stage to promote fruit setting and prevent hollow fruit.   Eggplant, 25~35mg/kg during flowering stage, spray once to promote fruit setting and increase yield.

For pepper, spray 20~40mg/kg once during flowering period to promote fruit setting and increase yield.

For watermelon, spray 20mg/kg once on flowers during the flowering stage to promote fruit setting and increase yield, or spray once on young melons during the young melon stage to promote growth and increase yield.

(4) gibberellic acid (GA3) extends the storage period
For melons, spraying the fruits with 2.5~3.5mg/kg liquid before harvesting can extend the storage time.

Spraying banana fruits with 50~60mg/kg liquid before harvesting has a certain effect on extending the storage period of fruits.   Jujube, longan, etc. can also delay aging and extend the storage period with gibberellic acid (GA3).

(5) gibberellic acid (GA3) changes the ratio of male and female flowers and increases seed yield
Using the female line of cucumber for seed production, spraying 50-100mg/kg liquid when the seedlings have 2-6 true leaves can turn the female cucumber plant into a monoecious plant, complete pollination, and increase seed yield.

(6) gibberellic acid (GA3) promotes stem flowering and improves the breeding coefficient of improved varieties.

Gibberellic acid (GA3) can induce early flowering of long-day vegetables.   Spraying plants or dripping growing points with 50~500 mg/kg of gibberellic acid (GA3) can make carrots, cabbage, radish, celery, Chinese cabbage, etc. grow sunshine crops for 2 years.   Bolt under short day conditions before overwintering.


(7) gibberellic acid (GA3) relieves the harm caused by other hormones
After vegetables are damaged by overdose, treatment with 2.5~5mg/kg gibberellic acid (GA3) solution can relieve the damage caused by paclobutrazol and chlormequat;  

 treatment with 2mg/kg solution can relieve the damage caused by ethylene.  

Tomato damage caused by excessive use of anti-falling agents can be eliminated with 20mg/kg gibberellic acid (GA3).